RECENT SUBMISSION

• Publication

  Antioxidative properties of Diplazium Esculentum extract by using pressurized hot water extractor: optimization study

  ( 2010)

  Nur Azirah Jamial

  Pressurized hot water extraction (PHWE) was implemented in attempt to reduce the use of toxic organic solvent in extracting bioactive compounds from Diplazium esculentum. Comparison extraction methods were done and the results shows that the PHWE had higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity (70%) and total phenolic contents (118.83f.lg catechin equivalentlmg dry samples) c,.ompared to autoclaving, boiling, soaking, sonicating and Soxhlet extraction. Soaking extraction had the highest total flavonoids contents (28.03f.lg rutin equivalentlmg dry extract). By applying Box-Behnken design of response surface methodology, the optimized condition for the best antioxidant activity of PH WE was at 17SoC, 21 minutes extraction time and SOmL water volume added to 2g of dried ground D. esculentum. The DPPH antiradical efficiency was analyzed where the D. esculentum extracts had ECso value of 1241.14f.lg/mL and time to reach steady state (TEC50) was 79.83 minutes. Thus, the extract was categorized as slow in scavenging the DPPH free radicals. Through HPLC, the identified flavonoids in the crude extracts were quercetin and myricetin.
• Publication

  Synthesis and optimization studies of Fructose palmitate

  ( 2010)

  Azalina Mohamed Nasir

  Fructose palmitate (sugar ester) is a relatively new class of nonionic surfactants. Their excellent biodegradability and low toxicity surfactant as well as effectiveness at extreme temperature, pH and salinity show their increasing importance in numerous areas of application. For a long time, large scale production of sugar ester was dominated by conventional chemical processing. However, the conventional chemical process leaves out bad impact to the human and environment. Compared to the enzymatic synthesis, this process offers a safer and easier alternative. In the present work, sugar ester production was developed by a novel and effective enzymatic method which can reduce the advantages of conventional chemical process. Direct unprotected sugar and non activated fatty acid were used as a starting material. Combination of supersaturated sugar solution under anhydrous condition and stepwise addition of molecular sieve as water absorbent agent during the reaction were found to be a suitable method in increasing the reaction rate and fatty acid conversion. In this method, influences of several parameters were investigated as a screening to the optimization process. Results from screening were used to optimize and analyze fructose palmitate (sugar ester) esterification using a response surface methodology (RSM) based on central composite design (CCD). The 98.58 ± 0.52% of optimum fatty acid conversion was determined by 11.92% (w/w of substrates) immobilized enzyme loading, 0.50M fatty acid concentration, 10.0h reaction time and 53.67oC of reaction temperature. The reusability of the immobilized enzyme was shown good conversion, were greater than 88% of fatty acid conversion after 10th reaction cycles without additional treatment of the immobilized enzyme.
• Publication

  Thermo-enzymatic hydrolysis of bitter Cassava starch: fundamental and process optimization studies

  ( 2010)

  Noorulnajwa Diyana Yaacob

  Fundamental characterization of cassava starch that will be used in bioethanol production was studied entensively. In the present study, non edible cassava (Manihot esculenta) is used as the raw material for starch, which undergoes enzymatic hydrolysis to produce glucose then precede the fermentation to obtain bioethanol. Proximate analysis of this starch showed that the carbohydrate content is 91.17% while apparent and total amylose are 16.6% and17.1% respectively. Phosphorus and ash showed the lowest value and the moisture content is 10.5%. Nitrogen and Total fat are negligible. By using various analytical equipments, its characteristics were identified. It was found that the root starch has a polyhedric shape by visualizing under SEM and the surface was smooth with no evidence of pores. Under XRD, the pattern shows that the cassava was classified as A-type starch and their gelatinization temperature was high, 89.4°C. Swelling and solubility take place as a result of gelatinization of starch granule. All the fundamental characteristics, gave a good impact for this starch to be used as a raw material in bioethanol industry. Enzymatic hydrolysis of starch from natural sources finds potential application in commercial production of bioethanol. The effects of various process variables were studied for optimum conversion of cassava starch to glucose using α-amylase and amyloglucosidase. Starch is a reserved polysaccharide of plant origin, which cannot be converted to sugar easily. Starch saccharification requires prior gelatinization by heat treatment, liquefaction by α- amylase and conversion to sugars by amyloglucosidase. In order to get higher glucose concentration; liquefaction and saccharification processes must be optimized. Full factorial composite experimental design and central composite design (CCD) were used in the design of experiments and analysis of results. Preliminary study was done to investigate the potential variable for these two processes. The performance of α- amylase in liquefaction was determined by dextrinizing activity (D.A.) while the performance of amyloglucosidase was based on glucose concentration. The optimal condition for liquefaction for 35% cassava starch slurry was obtained by using 0.33% BAN480L in sodium acetate buffer (pH 7) at 85°C for 12.72 min. The optimal conditions for sacharification were found to be at 60.75°C, pH 4.53, using 0.2% AMG300L in 40 min. A model adequacy was very satisfactory, as coefficient of determination were 0.9977 and 0.9795 for liquefaction and sacharification, respectively.
• Publication

  Studies on the production of Glucose oxidase by Aspergillus terreus UniMAP AA-1

  ( 2011)

  Ahmad Anas Nagoor Gunny

  Glucose oxidase (GOx) has found a wide range of applications in chemical, food, beverage, biotechnology and other industries. It is commonly extracted from Aspergillus niger and selected strains of Penicllium sp. Currently there is a growing need to find alternative sources of this enzyme due to some drawbacks associated with A.niger and Penicllium sp. In this work, a novel GOx-producing strain, Aspergillus terreus UniMAP AA-1, was isolated from soil of Agrotech Research Centre, Sg Chucuh, Perlis.The screening tests for the GOx-producing strain were carried out on the basis of color development test by using agar plate containing o-anisidine and horseradish peroxidase. The screened strain was identified morphologically using light microscope and Scanning Electron Microscope (SEM) and further verified by molecular level identification. The strain was identified as a predominant extracellular GOx producer and exhibits a pelleted morphology in fermentation culture. These findings offer a new alternative to the existing GOx-producing strains which are known to be associated with few drawbacks. Subsequently, a sequential optimization based on statistical design and one-factor-at-a-time (OFAT) method was employed to optimize the production of extracellular GOx from the potential strain. Plackett-Burman design indicated glucose as the most influential variable followed by NaNO3, CaCO3, and peptone on the GOx activity; while KH2PO4, MgSO4.7H2O and FeSO4.7H2O showed negative main effect on the enzyme activity. Based on the result, glucose, NaNO3 and CaCO3 were selected for further optimization studies. The influences of the three medium components were investigated with one-factor-at-a-time (OFAT) and these variables were subsequently optimized using a face centered central composite design (FCCCD). The optimum conditions were found to be 10.64% (w/v), 1.21% (w/v) and 5.22% (w/v) for glucose, NaNO3 and CaCO3 respectively and the enzyme activity was found to be 6.72 U/ml, which was about seven fold higher than that obtained in media before optimization. The oxygen and glucose consumption as well as hydrogen peroxide and gluconic acid production profiles of the crude enzyme are all in-line with typical GOx properties. The kinetic constant, Km of the crude enzyme for its substrate, determined by direct fits of Michaelis–Menten equation through nonlinear regression (with correlation value or R2 =0.98) using solver function in Microsoft Excel software, gave the value of within the range of 7.5-15 mM. The result indicates substrate specificity of the crude enzyme towards β-D glucose (substrate) and demonstrated the tight binding of the crude enzyme with its substrate.
• Publication

  Bovine Adipose tissue derived stem cells bioengineering: isolation, characterization and differentiation studies

  ( 2013)

  Fhataheya Buang

  There is a significant potential for stem cells to be exploited for regenerative medicine. Stem cells act as a repair system for the body by differentiating into specialised cells and replenishing cells in regenerative organs such as skin or intestinal tissues. Conventionally in the current cell therapy, the renewed, differentiated cells were mostly sourced form bone marrow mesenchymal stem cell (MSCs) yielding low number of cells and involved a painful procedure under general anaesthesia. In tissue engineering, bioprocessing stem cells are crucial thus, stem cells from adipose tissue were revealed as a new promising source of MSCs. Abundant source of stromal vascular fraction (SVF) needs a good bioprocessing tools for an optimize culture. Isolation of bovine adipose tissue derived stem cells (ASCs) are found to better perform in 0.075% collagenase Type 1 and agitated for 2 hours from the experiment carried out. The static cultures were best inoculated at 1.0 x 104 cells/ml in 6 well plate. The suspension cultures were cultured best in 200rpm, 5ml DMEM: F12 / MesenPRO RS™ at 1.0 x 104 cells/ml in 50ml tube. Suspension (3D) culture of sphere aggregates yield cells density of 1.07 x 106 ASCs upon culture compared to static (2D) culture of 5 x 105 ASCs on average. However the viability of static culture are found to be more superior to suspension culture at high volume, agitation and inoculation sizes suggesting that the parameter are an unfavourable environment to culture in 50ml tubes. Successful differentiation of osteoblast cells were evaluated via Fourier Transform Infra-Red (FTIR) and conventional Van Kossa staining. Simulation of suspension (3D) culture via Computational Fluid Dynamic (CFD) using Volume of Fluid (VOF) model assist in developing an optimised ASCs culture protocol vis-à-vis conventional static (2D) culturing in flask.